From ETH in Zurich, this interesting essay on the last glacial period has some interesting points to ponder. h/t to Sid Stafford – Anthony
The last glacial period was characterised by strong climatic fluctuations. Scientists have now been able to prove very frequent and rapid climate change, particularly at the end of the Younger Dryas period, around 12,000 years ago. These fluctuations were accompanied by rapid changes in circulation in the oceans and the atmosphere.
Sediment deposits in lakes are the climate archives of the past. An international team of researchers from Norway, Switzerland and Germany have now examined sediments originating from the Younger Dryas period from the Kråkenes Lake in northwest Norway. In the sediments, they found clues that point to a “climate flicker” at the end of the last glacial period, oscillating between colder and warmer phases until the transition to the stable climate of the Holocene, our current interglacial period. The short-term, strong fluctuations of the Younger Dryas would have dwarfed the “extreme weather phenomena” seen today, according to Gerald Haug, professor at the Department for Earth Sciences at ETH Zürich and co-author of the study, which was published online yesterday in “Nature Geoscience”.
Seasonal sediment deposits
Seasonal sediment accumulation, for example, gave scientists clues to these strong climate fluctuations. They can be read in lakes in a similar way to reading rings on trees. In warmer phases and melting glaciers, the accumulation of sediments increases. More clues on the changes in glacier growth were given by the element titanium, which is present in the sediments. Glaciers erode their bedrock, and in doing so concentrate the titanium contained in the sediments they are carrying. The sediments containing titanium are washed into the glacier’s draining lakes in the meltwater. The amount of sediment and the titanium content can therefore allow us to deduce when the glaciers were stable and when they melted. The researchers interpreted the maxims, recurring every 10 years, as phases of strong glacier activity caused by temperature fluctuations and thus as warmer times.
A seemingly self-preserving cycle
The scientists also examined a sediment core from seabed deposits of the same age in the North Atlantic. They reconstructed the original temperature and salt concentration of the water based on microfossils and the oxygen isotope ratio in the sediment. It was shown that the results from the lake sediments corresponded to those from the sea sediments. “The melting of glaciers was caused by the warm Gulf stream advancing into this region,” Gerald Haug explains. This increase in temperature caused the west winds to shift to the north and brought warm air to northern Europe. However, the meltwater draining into the Atlantic lowered the salt concentration and the density of the surface water, changing the convection in the ocean, which in turn allowed new sea ice to form. Subsequently, the Gulf Stream and the west winds were again forced out of the North Atlantic area and the region cooled down once again. These processes were repeated for around 400 years, until the current interglacial period was able to stabilise itself.
The Würm glaciation began around 100,000 years ago and lasted until around 10,000 years ago. In this period, there were strong fluctuations between warm and cold phases, particularly in the North Atlantic area. The Younger Dryas, which ushered in the current interglacial period, is one of the best-known and best-researched abrupt climate changes of that glaciation. It began around 12,900 years ago and at first caused an abrupt temperature drop in the northern hemisphere, as well as a temperature rise of up to 10°C in less than 20 years towards the end, around 11,700 years ago.
Unclear mechanisms
Up until now, there have been several studies which document the glacial conditions during the Younger Dryas period of 1,200 years. However, the mechanisms which caused it, sustained it and finally led to an interglacial period have yet to be fully understood. The researchers believe that further high-resolution studies of this type could give insights into how glacial periods are triggered and how they are brought to an end.
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(Bill Green)
I agree, “previous rapid temp. fluctuations is a deal-breaker for the alarmists”.
10C change in 20 years is testament to that.
12,000 years ago life on this planet survived many rapid fluctuations in climate over a 1200 year period. That robustness must be due to evolution, an inherent ability to adapt quickly to climate change.
Mitigation as proposed by alarmists now runs counter to humanity’s own ability to adapt to and exploit climate change. Mitigation in this form can now be looked upon as simply a political and social tool to control our own natural behaviour.
This study adds weight to the arguement that mitigation is likely to bring more human misery than adaption.
There is plenty of evidence for rather drastic ecological effects of these abrupt climate changes, though mainly for the shifts to colder and drier climate. These include large-scale forest die-off, continental-scale dust-storms and abrupt disappearance of animals (including humans) from northern areas.
Abrupt warmings are less visible, since it takes more time for animals and plants to react and invade newly suitable habitat, they show up best for very mobile animals like insects and birds.
How does the “short primer” about CO2 fit in:
Thanks for the continuing investigation into rapid climate change and glaciation/interglacials. Bill Green wrote: “The alarmists always say that the crisis lies in the rapidity of the change. If the T has changed so rapidly in the past, and there is still life on earth…no need for alarm.” Two points here. 1. I think we all will be alarmed if the climate changes so quickly. 2. The AGWers will turn any new evidence to their purposes — IMO to reduce the wealth of developed nations. Evaporated affluence and the means for productivity (a drought of human causation) will make it ever more difficult to adapt to rapid climate change whenever those conditions arises.
All my science publications seem to be part of the alarmist propaganda machine. I would like to know where this Nature article places that super-molecule CO2 in this skulduggery. Or, perhaps, some new alarmist entity will be added.
Without putting up a link (Google will find stuff), the thinking about the Youger Dryas lately has been that it was “triggered” by a comet impact approximately around the western Great Lakes area, melting the glacier there enough to change the drainage toward the St Lawrence instead of the Mississippi. The cold period immediately after the impact was extended ~1000 yrs by the huge fresh-water pulse into the N Atlantic. This also coincides w/the period of N Amer extinctions.
There is still arguments about the exact timing, tho.
“What implications does this have for the theory of man-made global warming?”
At a minimum, I would say this is circumstantial evidence that the warming we’ve seen is neither unprecedented in rate or magnitude. I expect it to be completely 100% dismissed by the strap-hangers over at ReallybadClimate.
@Fred
Thanks for the rant. I’ve been too sluggish to come up with my own. Nice job. Made me smile.
Is this “The Day after tomorrow II ?. It won´t happen anyway.
Ceolfrith (22:44:30) :
“Off Topic
Someone had been reading too much Jules Verne” :Worst than that, perhaps reading Al-Qaeda´s Jihad .Please do not even dare to make such crazy experiments! What Dr Roger Angel (or Devil?) is proposing it is plain madness.
Bingo!
People who know more about climate history seem to be less alarmed by recent changes. We can say with great certainty that climate has naturally changed rapidly in the past. The polar bear survived all the ups and downs.
BTW: What’s the margin of error for measuring climate. How certain are we that observed changes over the last 100 years are outside the margin of error for measuring those changes?
OT:
Ceolfrith, it seems that that kind of thing may be the alarmists next step. Hurry up and create some massive project that they can then give credit to for the cooling. How else can they avoid being revealed as fools or worse?
We shouldn’t be reading aricles like this and trying to make sense of phenomena such as climate “flicker”. The media, sponsored by a money trail as torturous as a rattlesnake’s winding path in the sand, is telling us that CO2, and by extension the common humanoid on the street, is factually responsible for all our ills. These articles should be burned. We only need the facts. Not the context, interpretations or meanings behind the facts.
Fahrenheit_451
Realitycheck,
You make an interesting argument. However, if we know “the end is not nigh”, then there is no impetus to change the status quo. With no calamity in sight, there is no need for politician’s grandiose plans and massive influx of dollars for their sycophants, and thus civilization, as we know it collapses.
Um, oh, I think I get it now. When AGW dies noisily, messily and painfully for all, a new and even more heinous event appears, thereby assuring full political employment for those so inclined to dine from the public trough.
Sorry, I always was the slow one in school…
Mike
Gulf current is expected to be colder this year, what will cause less tropical storms of real magnitude as to be called hurricanes, but, as usual, these will be “properly” named. With La Nina and PDO around I am sure nobody sees a Gore´s scenarium of a Gulf current melting artic ice and changing sea water salinity.
I like this statement:
“The researchers believe that further high-resolution studies of this type could give insights into how glacial periods are triggered and how they are brought to an end.”
It seems there’s an implication that we could trigger and end glacial periods at will. Hmmm….
“It seems to me this idea of previous rapid temp. fluctuations is a deal-breaker for the alarmists”
You would think so, but this is not how it works. The argument very seriously being offered is that previous rapid fluctuations are evidence for the alarming nature of the present warming. What was at first cited as alarming was the alleged unprecedentedness. The argument then was, this has never happened before, therefore it must be CO2 that causes it.
Now that that argument looks like its in peril, because it has happened pretty often before, the argument being used goes: well, it doesn’t matter. It is not admitted that the Hockey Stick was wrong. But it is argued that if it was wrong, that strengthens the alarmist argument.
If there have been previous fluctuations, this shows the climate is more susceptible to forcing that we thought, so this makes it more important, not less, to eliminate all forcing, and that means that even more, we should stop putting all that CO2 into the atmosphere.
So either way, we got to be alarmed. Obviously unprecedented warming would be alarming. But so would precedented warming.
I know, its nuts. But this really is how the argument is being run.
Anthony
I am sure that you are aware that ther have been a numbner of these flickers in the past, that is to say that there has been sudden and rapid climate change before. Dr Richard Alley, although a little bit on the warmers side has said on many occasions that sudden changes in climate can beed seen in the Greenland ice cores.
One interesting study, back in the 70’s, by George Denton at University of Maine, showed that sudden changes occured as the last ice age approached.
At 115,000 , 110,000, 90,000 and then several shallow changes around 70,000 yrs ago the planet cooled sharply. The 90,000 yr cooling was particularly fierce and sudden and lasted about 1000 yrs.
When he looked at the last ice age these changes became more and more frequent until the plunge into full ice age about 40,000 yrs ago.
So does climate change without man, yes. Does climate change gradually? Well there is little evidence that it does. Does it change suddenly? YES.
Where are we now in the cycle of ice ages? We are approaching the years when sudden changes started to occur the last time. BUT remember, the human life time is miniscule in these time scales.
And if one more idiot from the RC club mentions tipping point è-è-‘-è(è_))_;;;
Has anyone noticed the SOI has reached 17.2? La Nina type conditions to continue?
http://www.bom.gov.au/climate/enso/
Yes, but since it has not been peer reviewed by the team, we can’t trust its results or its methods.
[snip]
It is entirely possible that the rapid changes at the end of the Younger Dryas period are the causation of the current oscillations that we now see in PDO, AMO, SOI, ENSO and MOUSE(LOL). Just a thought.
A new paper in the Feb 27 issue of Science apparently implies that CO2 reduction led to lower temperatures and antarctic ice sheet development. I do not have a paid subscription so cannot verify. I can only read a description at
http://www.physorg.com/news154883447.html
This seems to contradict the temp-leads-CO2 idea.
Could someone with a subscription have a look at the paper maybe to see what they are actually reporting?
foinavon (03:42:15) Ice Age is not global cooling? So the 100 meter drop in sealevel was only in the northern hemisphere? 90% of 100,000 years is only “a period”?
This climate change, as opposed to the weather change the IPCC has hung its hat on, has been well known for decades by anyone who has investigated paleo climate in the last 50 years. The fantasy of AGW is just a political power grab. We need to be figuring out how to survive without crops north of 30 degrees, short growing seasons, and if we can influence climate forcings that we don’t understand to prolong the point of termination of this interglacial which is imminent in climatic scales. We do not understand climate!!!!
crosspatch (00:12:52) :
I don’t dispute your comments regarding precedence, but I think research into the Younger Dryas is not particularly applicable to our current climate. We are not in any way (i>enjoying similar climatic conditions as were present then.
beng (06:07:07) :
I don’t know about comet impacts in the Great Lakes area, but I am aware of the hypothesis about rapid melting on the southern margin of the Laurentide ice sheet contributing the the Younger Dryas through disruption of the North Atlantic oceanic circulation. It looks as though the research highlighted above supports this hypothesis.
This catastrophism is of psychiatric origin: “Level 1 Defense Mechanisms – Almost always pathological; for the user these three defenses permit someone to rearrange external reality (and therefore not have to cope with reality); for the beholder, the users of these mechanisms frequently appear crazy or insane. These are the “psychotic” defenses, common in overt psychosis, in dreams, and throughout childhood. They include:
Denial – a refusal to accept external reality because it is too threatening. There are examples of denial being adaptive (for example, it might be adaptive for a person who is dying to have some denial.
Distortion – a gross reshaping of external reality to meet internal needs Delusional Projection – frank delusions about external reality, usually of a persecutory nature ”
Link: http://drsanity.blogspot.com/2004/08/psychiatry-101-defense-mechanisms.html
Interesting that these events should have been witnessed by our ancestors.
It would easily account for the wide spread stories of a universal flood found amongst 300 different cultures.
Sitting here at 3201 feet in Missoula, I can see not less than 30 strandlines on Mt Sentinel to the east. These lines, reaching elevations of more than 4000 feet, are old Lake Missoula shorelines, created as the lake was repeatedly formed behind ice dams near what is now Lake Pend Oreille. These ice dams formed, failed and were reformed many times in the last 20,000 years of the most recent ice age. Would all that activity be correctly interpreted as a flicker? Haven’t seen a flicker like that since I put a nickel in an Edison machine.